The Internet provides for the collective resources available within large networks to be shared among users. The growth of the Internet has allowed sharing of computer resources to be brought to wide audiences. For many companies, Internet sites are an integral part of the business, offering customers detailed information on available products, providing customers with a direct means of making purchases, and serving as a conduit between technical support operations and customers in need of service.
Digital information displayed on the Internet may be found on web pages viewed through a web browser. A web page is a HyperText Markup Language (HTML) file containing both text and a set of HTML tags that describe how the text should be formatted when the web browser displays the web page on a user's display screen. A web browser is a computer program capable of accessing a web server on the Internet, requests the web page, and retrieves the page so that a user can view HTML documents and access files and programs related to those HTML documents. A web server is a program that uses Hypertext Transfer Protocol (HTTP), or related protocols, to provide HTML documents and files and programs related to those documents when requested by a web browser. The web browser then interprets the HTML tags within the page and displays the page.
JavaScript® is an interpreted computer programming language. The most common use of JavaScript® is to write functions that are embedded in or included within HTML pages and interact with the Document Object Model (DOM) of the page. The DOM is a standard developed at the World Wide Web consortium for a platform- and language-independent interface to the structure and content of HTML and Extensible Markup Language (XML) documents. JavaScript® provides the tools to manipulate the objects in a Web page. The DOM is the specification for how all those objects are represented. The DOM allows JavaScript® to programmatically access and manipulate the contents of a document. The DOM defines: each object on a Web page, attributes associated with those objects, and methods that can be used to manipulate those objects. By using the DOM, JavaScript® can dynamically update the content, structure, and style of Web pages.